With respect to the Periodic Table, how do ionization energies differ?
But decrease down a Group. We have antimony, and bismuth, Group 15 elements, and thus we would expect,
But a scientist interrogates data. And we have no data.....
This graph gives the first ionization energy; it also gives the definition, where both reactant and oxidized product are in the gaseous phase:
You are going to have dig for successive ionization energies in order to illustrate your argument. So find the data first!